Numerous studies have identified a relationship between nurse staffing levels and adverse outcomes for medical and surgical patients including pressure ulcers, patient falls, and medication errors, among others. Because these adverse events can be linked to nursing care and staffing levels, they're often referred to as `nurse-sensitive' outcomes. Nurse-sensitive outcomes are defined as a condition, state, or perception (of either the patient or family caregiver) that is responsive to the action of the nurse. Despite wide range of studies on nurse-sensitive outcomes for medical and surgical patients in the acute care setting, little has been published on what constitutes a nurse- sensitive outcome in the childbearing woman, and even less that assesses the influence of nurse staffing on adverse obstetrical (OB) events. Low staffing numbers in ICUs (including newborn ICUs [NICUs]) are associated with increased morbidity and mortality although it is not known to what extent (if any) staffing levels in labor and delivery (L&D) influence subsequent NICU admissions or other adverse events such as unanticipated cesarean births. Using Donabedian's classic Structure, Process, and Outcomes (SPO) model, this innovative study will determine whether a relationship exists between L&D nurse staffing and adverse maternal and newborn outcomes. The specific aims of this study are as follows: (a) determine the influence of L&D nurse staffing on the likelihood of cesarean birth in term gestation (>37 weeks) low-risk first birth mothers with a single fetus, and (b) Determine the influence of L&D nurse staffing on the likelihood of NICU admissions or newborn transfers (for those hospitals without an NICU) to term gestation low-risk first-birth mothers with a single fetus. Understanding the link between perinatal nurse staffing and maternal and neonatal well- being is fundamental to enhancing outcomes and promoting patient safety in the childbearing family .If the relationships indicate these outcomes are staffin sensitive, it will allow further studies that examine whether manipulating staffing levels can mitigate adverse birth outcomes.